The
Civil War was unlike other wars Americans had faced: the enemies were fellow
Americans, not foreigners. The conflict touched every part of the nation, and Lincoln particularly worried about the presence of Confederate
supporters in the northern and border states. These individuals were capable of
aiding the southern forces without joining the Confederate Army. Of special concern
were the large numbers of southern sympathizers known as Copperheads, who were
active in Indiana, Illinois, Ohio, and Missouri. Combating these civilian enemies posed a difficult problem
for the president. He decided that the Union was more important than the procedural rights of
individuals. Consequently, Lincoln gave his military commanders broad powers to arrest
civilians suspected of engaging in traitorous activities. These suspects were
to be tried in military courts.

In
those areas of the country where hostilities were not occurring, however, the
army had no legal authority to arrest and try civilians. State and federal
courts were in full operation and were capable of trying civilians charged with
treason or any other crime. To allow arrests and military trials for civilians
a state of martial law had to be declared, and to do
that, the right of habeas corpus had to be suspended. Habeas corpus is a legal
procedure with roots extending far back into English legal history; it permits
an arrested person to have a judge determine whether the detention is legal. If
the court determines that there are no legal grounds for the arrest, it may
order the release of the detained individual. Habeas corpus is essential to the
doctrine of checks and balances because it gives the judiciary the right to
intervene if the executive branch abuses the law enforcement power.

Article
I, Section 9, of the Constitution provides for the suspension of habeas corpus
in the following words: “The Privilege of the Writ of Habeas Corpus shall not
be suspended, unless when in Cases of Rebellion or Invasion the public Safety
may require it.” This provision posed two problems for Lincoln. First, the suspension provision is found in Article I,
which outlines legislative, not executive, powers. And second, if the civilian
courts are in full operation and no armed hostilities are taking place in the
area, the public safety probably does not demand a suspension of habeas corpus
procedures.

These
obstacles did not stop the president. Several times during the war he issued
orders expanding military control over civilian areas, permitting military
arrests and trials of civilians, and suspending habeas corpus. Congress later
endorsed some of these actions. Arrests of suspected traitors and conspirators
were common and often based on little evidence. Were such actions
constitutional under the war powers doctrine? The Court addressed this question
in Ex parte
Milligan (1866), a decision of great importance in defining the wartime
powers of the chief executive.

Lambdin
P. Milligan was an attorney residing in southern Indiana. As a member of the Democratic Party, with strong states’
rights beliefs, his sympathies lay with the Confederate cause during the war.
He openly organized groups and gave speeches in support of the South. He also
was involved in efforts to persuade men not to join the Union army. At one
point Milligan and his fellow Copperheads were suspected of hatching a plan to
raid prisoner of war camps in Illinois, Indiana, and Ohio and release the imprisoned Confederate soldiers, who would
then take control of the three states. Federal military investigators followed
Milligan closely and kept records of his activities and contacts.

On October 5, 1864, under orders from Gen. Alvin Hovey, commander of the Union armies in Indiana,
federal agents arrested Milligan at his home. They also arrested four of
Milligan’s fellow Confederate sympathizers. Sixteen days later Hovey placed Milligan on trial before a military tribunal
in Indianapolis. He was found
guilty and sentenced to be hanged on May
19, 1865. On May 2, less than a month after the war ended with
General Lee’s surrender at Appomattox,
President Andrew Johnson, who had succeeded Lincoln,
sustained the order that Milligan be executed. In response, Milligan’s
attorneys filed for a writ of habeas corpus in federal circuit court, claiming
that Milligan should not have been tried by a military tribunal and that the
president should not have suspended the writ of habeas corpus. Uncertain of how
to apply the law, the circuit judges requested that the Supreme Court resolve
certain questions regarding the legal authority of a military commission to try
and sentence Milligan.

Nine
months later, in March 1866, the Court heard the Milligan case. Oral arguments took place at a time of heightened
political tension. Relations were strained between Johnson, who supported a
moderate position toward the reintroduction of the southern states into the Union, and the Radical Republicans in Congress, who demanded a
more severe Reconstruction policy. A majority of the justices opposed the
military trials at issue in Milligan,
but there was concern about possible congressional retaliation if the justices
struck a blow against military authority. The Court at this point was quite
vulnerable, having suffered a decline in prestige because of the infamous
decision in Scott v. Sandford.
But the justices had a potential ally in Johnson. The president opposed the use
of military tribunals, and the Radicals had not yet gained sufficient strength
to override a veto of a congressional act. On April 3, 1866, the Court announced its decision in Milligan, but formal opinions were not issued until eight months
later.

mr.
justice davis delivered the
opinion of the Court.

Milligan insists that
said military commission had no jurisdiction to try him upon the charges
preferred, or upon any charges whatever; because he was a citizen of the United
States and the State of Indiana, and had not been, since the commencement of
the late Rebellion, a resident of any of the States whose citizens were arrayed
against the government, and that the right of trial by jury was guaranteed to
him by the Constitution of the United States. . . .

The
importance of the main question presented by this record cannot be overstated;
for it involves the very framework of the government and the fundamental
principles of American liberty.

During
the late wicked Rebellion, the temper of the times did not allow that calmness
in deliberation and discussion so necessary to a correct conclusion of a purely
judicial question. Then,
considerations of safety were mingled with the exercise of power; and feelings
and interests prevailed which are happily terminated. Now that the public safety is assured, this question, as well as
all others, can be discussed and decided without passion or the admixture of
any element not required to form a legal judgment. We
approach the investigation of this case, fully sensible of the magnitude of the
inquiry and the necessity of full and cautious deliberation. . . .

The
controlling question in the case is this: Upon the facts stated in Milligan’s petition, and the exhibits filed, had
the military commission mentioned in it jurisdiction,
legally, to try and sentence him? Milligan, not a resident of one of the
rebellious states, or a prisoner of war, but a citizen of Indiana for twenty
years past, and never in the military or naval service, is, while at his home,
arrested by the military power of the United States, imprisoned, and, on
certain criminal charges preferred against him, tried, convicted, and sentenced
to be hanged by a military commission, organized under the direction of the
military commander of the military district of Indiana. Had this tribunal the legal power and authority to try and
punish this man?

No graver question was
ever considered by this court, nor one which more nearly concerns the rights of
the whole people; for it is the birthright of every American citizen when charged
with crime, to be tried and punished according to law. The power of punishment
is, alone through the means which the laws have provided for that purpose, and
if they are ineffectual, there is an immunity from punishment, no matter how
great an offender the individual may be, or how much his crimes may have
shocked the sense of justice of the country, or endangered its safety. By the
protection of the law human rights are secured; withdraw that protection, and
they are at the mercy of wicked rulers, or the clamor of an excited people. If
there was law to justify this military trial, it is not our province to
interfere; if there was not, it is our duty to declare the nullity of the whole
proceedings. The decision of this question does not depend on argument or
judicial precedents, numerous and highly illustrative as they are. These
precedents inform us of the extent of the struggle to preserve liberty and to
relieve those in civil life from military trials. The founders of our
government were familiar with the history of that struggle; and secured in a
written constitution every right which the people had wrested from power during
a contest of ages. By that Constitution and the laws authorized by it this
question must be determined. The provisions of that instrument on the
administration of criminal justice are too plain and direct, to leave room for
misconstruction or doubt of their true meaning. Those applicable to this case
are found in that clause of the original Constitution which says, “That the trial
of all crimes, except in case of impeachment, shall be by jury;”. . .

Time
has proven the discernment of our ancestors; for even these provisions,
expressed in such plain English words, that it would seem the ingenuity of man
could not evade them, are now, after the lapse of more than seventy years,
sought to be avoided. Those great and good men foresaw that troublous times
would arise, when rulers and people would become restive under restraint, and
seek by sharp and decisive measures to accomplish ends deemed just and proper;
and that the principles of constitutional liberty would be in peril, unless
established by irrepealable law. The history of the
world had taught them that what was done in the past might be attempted in the
future. The Constitution of the United States is a law for rulers and people,
equally in war and in peace, and covers with the shield of its protection all
classes of men, at all times, and under all circumstances. No doctrine,
involving more pernicious consequences, was ever invented by the wit of man
than that any of its provisions can be suspended during any of the great
exigencies of government. Such a doctrine leads directly to anarchy or
despotism, but the theory of necessity on which it is based is false; for the
government, within the Constitution, has all the powers granted to it, which
are necessary to preserve its existence; as has been happily proved by the
result of the great effort to throw off its just authority.

Have
any of the rights guaranteed by the Constitution been violated in the case of
Milligan? and if so, what are they?

Every
trial involves the exercise of judicial power; and from what source did the
military commission that tried him derive their authority? Certainly no part of
the judicial power of the country was conferred on them; because the
Constitution expressly vests it “in one supreme court and such inferior courts
as the Congress may from time to time ordain and establish,” and it is not
pretended that the commission was a court ordained and established by Congress.
They cannot justify on the mandate of the President; because he is controlled
by law, and has his appropriate sphere of duty, which is to execute, not to
make, the laws; and there is “no unwritten criminal code to which resort can be
had as a source of jurisdiction.”

But
it is said that the jurisdiction is complete under the “laws and usages of
war.”

It
can serve no useful purpose to inquire what those laws and usages are, whence
they originated, where found, and on whom they operate; they can never be
applied to citizens in states which have upheld the authority of the
government, and where the courts are open and their process unobstructed. This
court has judicial knowledge that in Indiana the Federal authority was always
unopposed, and its courts always open to hear criminal accusations and redress
grievances; and no usage of war could sanction a military trial there for any
offence whatever of a citizen in civil life, in nowise connected with the
military service. Congress could grant no such power; and to the honor of our
national legislature be it said, it has never been
provoked by the state of the country even to attempt its exercise. One of the
plainest constitutional provisions was, therefore, infringed when Milligan was
tried by a court not ordained and established by Congress, and not composed of
judges appointed during good behavior.

Why
was he not delivered to the Circuit Court of Indiana to be proceeded against
according to law? No reason of necessity could be urged against it; because
Congress had declared penalties against the offences charged, provided for
their punishment, and directed that court to hear and determine them. And soon
after this military tribunal was ended, the Circuit Court met, peacefully
transacted its business, and adjourned. It needed no bayonets to protect it,
and required no military aid to execute its judgments. It was held in a state,
eminently distinguished for patriotism, by judges commissioned during the
Rebellion, who were provided with juries, upright, intelligent, and selected by
a marshal appointed by the President. The government had no right to conclude
that Milligan, if guilty, would not receive in that court merited punishment;
for its records disclose that it was constantly engaged in the trial of similar
offences, and was never interrupted in its administration of criminal justice.
If it was dangerous, in the distracted condition of affairs, to leave Milligan
unrestrained of his liberty, because he “conspired against the government,
afforded aid and comfort to rebels, and incited the people to insurrection,”
the law said arrest him, confine him closely, render him powerless to do
further mischief; and then present his case to the grand jury of the district,
with proofs of his guilt, and, if indicted, try him according to the course of
the common law. If this had been done, the Constitution would have been
vindicated, the law of 1863 enforced, and the securities for personal liberty
preserved and defended. . . .

The
discipline necessary to the efficiency of the army and navy, required other and
swifter modes of trial than are furnished by the common law courts; and, in
pursuance of the power conferred by the Constitution, Congress has declared the
kinds of trial, and the manner in which they shall be conducted, for offences
committed while the party is in the military or naval service. Every one
connected with these branches of the public service is amenable to the
jurisdiction which Congress has created for their government, and, while thus
serving, surrenders his right to be tried by the civil courts. All other
persons, citizens of states where the courts are open, if charged with crime,
are guaranteed the inestimable privilege of trial by jury. This privilege is a
vital principle, underlying the whole administration of criminal justice; it is
not held by sufferance, and cannot be frittered away on any plea of state or
political necessity. When peace prevails, and the authority of the government
is undisputed, there is no difficulty of preserving the safeguards of liberty;
for the ordinary modes of trial are never neglected, and no one wishes it
otherwise; but if society is disturbed by civil commotion--if the passions of
men are aroused and the restraints of law weakened, if not disregarded--these safeguards
need, and should receive, the watchful care of those intrusted
with the guardianship of the Constitution and laws. In no other way can we
transmit to posterity unimpaired the blessings of liberty, consecrated by the
sacrifices of the Revolution.

It
is claimed that martial law covers with its broad mantle the proceedings of
this military commission. The proposition is this: that in a time of war the
commander of an armed force (if in his opinion the exigencies of the country
demand it, and of which he is to judge), has the power, within the lines of his
military district, to suspend all civil rights and their remedies, and subject
citizens as well as soldiers to the rule of his will; and in the exercise of
his lawful authority cannot be restrained, except by his superior officer or
the President of the United States.

If
this position is sound to the extent claimed, then when war exists, foreign or
domestic, and the country is subdivided into military departments for mere convenience,
the commander of one of them can, if he chooses, within his limits, on the plea
of necessity, with the approval of the Executive, substitute military force for
and to the exclusion of the laws, and punish all persons, as he thinks right
and proper, without fixed or certain rules.

The
statement of this proposition shows its importance; for, if true, republican
government is a failure, and there is an end of liberty regulated by law.
Martial law, established on such a basis, destroys every guarantee of the
Constitution, and effectually renders the “military independent of and superior
to the civil power”--the attempt to do which by the King of Great Britain was
deemed by our fathers such an offence, that they assigned it to the world as
one of the causes which impelled them to declare their independence. Civil
liberty and this kind of martial law cannot endure together; the antagonism is
irreconcilable; and, in the conflict, one or the other must perish.

This
nation, as experience has proved, cannot always remain at peace, and has no
right to expect that it will always have wise and humane rulers, sincerely
attached to the principles of the Constitution. Wicked men, ambitious of power,
with hatred of liberty and contempt of law, may fill the place once occupied by
Washington and Lincoln; and if this right is conceded, and the calamities of
war again befall us, the dangers to human liberty are frightful to contemplate.
If our fathers had failed to provide for just such a contingency, they would
have been false to the trust reposed in them. They knew--the history of the
world told them--the nation they were founding, be its existence short or long,
would be involved in war; how often or how long continued, human foresight
could not tell; and that unlimited power, wherever lodged at such a time, was
especially hazardous to freemen. For this, and other equally weighty reasons,
they secured the inheritance they had fought to maintain, by incorporating in a
written constitution the safeguards which time had proved were essential to its
preservation. Not one of these safeguards can the President, or Congress, or
the Judiciary disturb, except the one concerning the writ of habeas corpus.

It
is essential to the safety of every government that, in a great crisis, like
the one we have just passed through, there should be a power somewhere of
suspending the writ of habeas corpus. In every war, there are men of previously
good character, wicked enough to counsel their fellow-citizens to resist the
measures deemed necessary by a good government to sustain its just authority
and overthrow its enemies; and their influence may lead to dangerous
combinations. In the emergency of the times, an immediate public investigation
according to law may not be possible; and yet, the peril to the country may be
too imminent to suffer such persons to go at large. Unquestionably, there is
then an exigency which demands that the government, if it should see fit in the
exercise of a proper discretion to make arrests, should not be required to
produce the persons arrested in answer to a writ of habeas corpus. The
Constitution goes no further. It does not say after a writ of habeas corpus is
denied a citizen, that he shall be tried otherwise than by the course of the
common law; if it had intended this result, it was easy by the use of direct
words to have accomplished it. The illustrious men who framed that instrument
were guarding the foundations of civil liberty against the abuses of unlimited
power; they were full of wisdom, and the lessons of history informed them that
a trial by an established court, assisted by an impartial jury, was the only
sure way of protecting the citizen against oppression and wrong. Knowing this,
they limited the suspension to one great right, and left the rest to remain
forever inviolable. But, it is insisted that the safety of the country in time
of war demands that this broad claim for martial law shall be sustained. If
this were true, it could be well said that a country, preserved at the
sacrifice of all the cardinal principles of liberty, is not worth the cost of
preservation. Happily, it is not so.

It
will be borne in mind that this is not a question of the power to proclaim
martial law, when war exists in a community and the courts and civil
authorities are overthrown. Nor is it a question what rule a military
commander, at the head of his army, can impose on states in rebellion to
cripple their resources and quell the insurrection. The jurisdiction claimed is
much more extensive. The necessities of the service, during the late Rebellion,
required that the loyal states should be placed within the limits of certain
military districts and commanders appointed in them; and, it is urged, that
this, in a military sense, constituted them the theatre of military operations;
and, as in this case, Indiana had been and was again threatened with invasion
by the enemy, the occasion was furnished to establish martial law. The
conclusion does not follow from the premises. If armies were collected in Indiana, they were to be employed in another locality, where the
laws were obstructed and the national authority disputed. On her soil there was
no hostile foot; if once invaded, that invasion was at an end, and with it all
pretext for martial law. Martial law cannot arise from a threatened invasion.
The necessity must be actual and present; the invasion real, such as
effectually closes the courts and deposes the civil administration.

It
is difficult to see how the safety of the country required martial law in Indiana. If any of her citizens were plotting treason, the power of
arrest could secure them, until the government was prepared for their trial,
when the courts were open and ready to try them. It was as easy to protect
witnesses before a civil as a military tribunal; and as there could be no wish
to convict, except on sufficient legal evidence, surely an ordained and
established court was better able to judge of this than a military tribunal
composed of gentlemen not trained to the profession of the law.

the
chief justice delivered the
following opinion.

T]he opinion . . .
as we understand it, asserts not only that the military commission held in
Indiana was not authorized by Congress, but that it was not in the power of
Congress to authorize it, from which it may be thought to follow that Congress
has no power to indemnify the officers who composed the commission against
liability in civil courts for acting as members of it.

We
cannot agree to this.

We
agree in the proposition that no department of the government of the United States--neither President, nor Congress, nor the Courts--possesses
any power not given by the Constitution.

We
assent fully to all that is said in the opinion of the inestimable value of the
trial by jury, and of the other constitutional safeguards of civil liberty. And
we concur also in what is said of the writ of habeas corpus and of its
suspension, with two reservations: (1) that, in our judgment, when the writ is
suspended, the Executive is authorized to arrest, as well as to detain, and (2)
that there are cases in which, the privilege of the writ being suspended, trial
and punishment by military commission, in states where civil courts are open,
may be authorized by Congress, as well as arrest and detention.

We
think that Congress had power, though not exercised, to authorize the military
commission which was held in Indiana.

We
do not think it necessary to discuss at large the grounds of our conclusions.
We will briefly indicate some of them.

The
Constitution itself provides for military government, as well as for civil
government. And we do not understand it to be claimed that the civil safeguards
of the Constitution have application in cases within the proper sphere of the
former.

What,
then, is that proper sphere? Congress has power to raise
and support armies, to provide and maintain a navy, to make rules for the
government and regulation of the land and naval forces, and to provide for
governing such part of the militia as may be in the service of the United States.

It
is not denied that the power to make rules for the government of the army and
navy is a power to provide for trial and punishment by military courts without
a jury. It has been so understood and exercised from the adoption of the
Constitution to the present time. . . .

We
by no means assert that Congress can establish and apply the laws of war where
no war has been declared or exists.

Where
peace exists, the laws of peace must prevail. What we do maintain is that, when
the nation is involved in war, and some portions of the country are invaded,
and all are exposed to invasion, it is within the power of Congress to
determine in what states or district such great and imminent public danger
exists as justifies the authorization of military tribunals for the trial of
crimes and offences against the discipline or security of the army or against
the public safety. . . .

We
cannot doubt that, in such a time of public danger, Congress had power under
the Constitution to provide for the organization of a military commission and
for trial by that commission of persons engaged in this conspiracy. The fact
that the Federal courts were open was regarded by Congress as a sufficient
reason for not exercising the power, but that fact could not deprive Congress
of the right to exercise it. Those courts might be open and undisturbed in the
execution of their functions, and yet wholly incompetent to avert threatened
danger or to punish, with adequate promptitude and certainty, the guilty
conspirators. . . .